Effects of wording and stimulus format on the use of contingency information in causal judgment.

There are four kinds of contingency information: occurrences and nonoccurrences of an effect in the presence and in the absence of a cause. Previous studies have shown that these four kinds are not given equal weight in causal judgment. The present research was designed to test two hypotheses about this unequal weighting: that weightings are influenced by the form of the question and other features of the stimulus materials and that unequal weightings occur, in part, because individual differences in the use of contingency information are not evenly distributed across the four kinds of information. Support was found for both hypotheses. However, the effects of question wording were not always as had been predicted, indicating that more needs to be learned about how people interpret the task, instructions, and materials they are given.